As of 721a MT 04/10/22 I am not getting the 503 error anymore.
I am seeing new plates on the cloud.openalpr.com dashboard.
It doesn't appear that anything was uploaded to the cloud by the openalpr client between 04/09/22 11:47:09a MT and 04/10/22 07:21:00a MT.
My dashboard also came back up, all plates missing from outage period. Seems no new data is being fed in yet from my agent, or at least it is now showing up.
I never got the plates from that 7 hour blackout period. Actually I did get some, maybe about 10 plates, which makes me think it keeps some queue. Not a big deal to lose those plates for me luckily, but it would be nice if it saved them in a queue when the server is down.